Stock material or miscellaneous articles – All metal or with adjacent metals – Composite; i.e. – plural – adjacent – spatially distinct metal...
Reexamination Certificate
1998-06-18
2001-03-20
Jones, Deborah (Department: 1775)
Stock material or miscellaneous articles
All metal or with adjacent metals
Composite; i.e., plural, adjacent, spatially distinct metal...
C428S607000, C428S632000, C428S472300, C057S902000, C152S556000
Reexamination Certificate
active
06203932
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a brass-plated steel wire for reinforcement of rubber articles such as tires, industrial belts and the like, a method of manufacturing the wire, and a steel cord consisting of the wires twisted together, particularly aims to improve initial adhesion of the steel wire to rubber. Here, the initial adhesion means adhesion of steel wire to rubber at the initial stage of vulcanization when manufacturing rubber articles.
2. Related Art
In steel wire or steel cord consisting of wires twisted together used for reinforcement of rubber articles, good adhesion to rubber is required to obtain reinforcing effect. On improvement of the adhesion in steel wire or steel cord with brass-plating, it has been widely known that the adhesion can be more increased by appropriately determining Cz/Zn ratio of the brass plating, thickness of the brass plating and the like.
Moreover, Japanese Patent Application Laid-open No. SHO 62-23977 proposes a method of improving adhesion by applying copper and zinc plating to steel wire, then alloying the copper and zinc to form brass plating by thermal diffusion, and thereafter quenching the brass-plated steel wire with water, thereby controlling production of zinc oxide on the surface of wire.
Further, Japanese Patent Application Laid-open No. SHO 63-33135 proposes to mitigate deterioration of adhesion after steam aging by containing not less than 4 mg/m
2
of phosphorous in the brass plating of brass-plated steel wire.
However, in a method comprising quenching with water immediately after thermal diffusion as disclosed in the above Japanese Patent Application Laid-open No. SHO 62-23977, a quenching device is necessary, and also a dryer is necessary for preventing production of rust, so as to require places for setting these devices. As a result, it becomes difficult to produce a steel wire economically.
Moreover, in a steel wire containing phosphorous in the brass plating as disclosed in the above Japanese Patent Application Laid-open No. SHO 63-33135, adhesion to rubber after steam aging is improved, but adhesion at the initial stage of vulcanization is not sufficient to achieve economical production of rubber articles with shortened curing time for energy saving.
Furthermore, in case of manufacturing a cord consisting of steel wires having slightly different diameters, it takes a time to change drawing die schedule in ordinary wet drawing process.
An object of the present invention is to provide economical way to improve initial adhesion of steel wire or steel cord for reinforcement of rubber articles and to materialize shortening of curing time, thereby enabling economical production of rubber articles.
SUMMARY OF THE INVENTION
In order to solve the above problem, the present invention provides a steel wire for reinforcement of rubber articles, which has brass plating consisting of 60-70 wt % of copper and 30-40 wt % of zinc and coating film comprising phosphorous compound and zinc oxide on the surface of the brass plating, wherein amount of the phosphorous compound expressed in amount of phosphorous per unit surface area is within a range of not less than 0.2 mg/m
2
and not more than 0.9 mg/m
2
and amount of the zinc oxide per unit surface area is within a range of not less than 20.0 mg/m
2
and not more than 70.0 mg/m
2
.
Further, the present invention provides a method of manufacturing the steel wire for reinforcement of rubber articles of the present invention, which comprises the steps of drawing a carbon steel wire rod plated with brass and containing 0.65-0.95 wt % of carbon, through a group of dies immersed in a lubricant containing phosphate in continuous wet drawing, winding the resulting steel wire around a spool, mounting the spool on a pay off unit of a twister assembly to pay off the steel wire, and drawing the steel wire at a drawing unit comprising one or more dies arranged between the pay off unit and a twisting unit in the twister assembly and having an area reduction per die of at least 5%, to reduce the diameter of the steel wire.
In such manufacturing method, application of naphthenic hydrocarbon oil on the steel wire drawn in the continuous wet drawing may be adopted prior to drawing at the drawing unit arranged between the pay off unit and the twisting unit in the twister assembly.
Furthermore, the present invention provides a steel cord for reinforcement of rubber articles, which comprises a plurality of the steel wires of the present invention twisted together.
REFERENCES:
patent: 4683175 (1987-07-01), Bakewell et al.
patent: 4952249 (1990-08-01), Dambre
patent: 5014760 (1991-05-01), Bombeke et al.
patent: 5118367 (1992-06-01), Starinshak
patent: 5229215 (1993-07-01), Starinshak
patent: 5240520 (1993-08-01), Tarui et al.
patent: 5437748 (1995-08-01), Bhagwat et al.
patent: 61-190082 (1986-08-01), None
patent: 63-33135 (1988-02-01), None
patent: 6-293938 (1994-10-01), None
patent: 7-119057 (1995-09-01), None
International Search Report for PCT/JP96/03715.
Bridgestone Corporation
Jones Deborah
Stein Stephen
Sughrue Mion Zinn Macpeak & Seas, PLLC
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